In the formation of a fuel-metering signal, it is known to compute a base value of a fuel-metering signal from signals for the rpm and the intake-air quantity of the engine. This base value is corrected with further corrective quantities for adapting to operating conditions such as restart, warm running, acceleration, full load, et cetera. Additional corrections can, for example, result from requirements of overheating protective measures, knock-protective measures or even for catalytic converter heating measures. With an increasing number of corrective interventions, the probability increases that unwanted cumulative effects of simultaneous corrective interventions occur. For example, a cumulative enrichment because of knock protection, warm-up running and full load could effect an enrichment which exceeds the actual requirement. In the same way, corrections which effect a leaning (corrections, which are, for example, used for heating catalytic converters) can compensate in an unwanted manner with the above-mentioned enriching operating quantities.